1,622 research outputs found
Assessment of carotenoid production by Dunaliella salina in different culture systems and operation regimes
The effect of operation regime and culture system on carotenoid productivity by the halotolerant alga Dunaliella salina has been analyzed. Operation strategies tested included batch and semi continuous regime, as well as a two-stage approach run simultaneously in both, open tanks and closed reactor. The best results were obtained with the closed tubular photobioreactor. The highest carotenoid production (328.8 mg carotenoid l−1 culture per month) was achieved with this culture system operated following the two-stage strategy. Also, closed tubular photobioreactor provided the highest carotenoid contents (10% of dry weight) in Dunaliella biomass and β-carotene abundance (90% of total carotenoids) as well as the highest 9-cis to all-trans β-carotene isomer ratio (1.5 at sunrise).Comisión Interministerial de Ciencia y Tecnología IFD 1997-1780IFAPA CO3-125Plan Andaluz de Investigación CVI13
Étale Covers and Fundamental Groups of Schematic Finite Spaces
[EN] We introduce the category of finite étale covers of an arbitraryschematic space X and show that, equipped with an appropriate naturalfiber functor, it is a Galois Category. This allows us to define the étale
fundamental group of schematic spaces. If X is a finite model of a schemeS, we show that the resulting Galois theory on X coincides with theclassical theory of finite étale covers on S, and therefore, we recover
the classical étale fundamental group introduced by Grothendieck. Toprove these results, it is crucial to find a suitable geometric notion ofconnectedness for schematic spaces and also to study their geometric
points. We achieve these goals by means of the strong cohomologicalconstraints enjoyed by schematic spaces.Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE
Assessment of a Universal Reconfiguration-less Control Approach in Open-Phase Fault Operation for Multiphase Drives
Multiphase drives have been important in particular industry applications where reliability is
a desired goal. The main reason for this is their inherent fault tolerance. Di erent nonlinear controllers
that do not include modulation stages, like direct torque control (DTC) or model-based predictive
control (MPC), have been used in recent times to govern these complex systems, including mandatory
control reconfiguration to guarantee the fault tolerance characteristic. A new reconfiguration-less
approach based on virtual voltage vectors (VVs) was recently proposed for MPC, providing a natural
healthy and faulty closed-loop regulation of a particular asymmetrical six-phase drive. This work
validates the interest in the reconfiguration-less approach for direct controllers and multiphase drives
The central parsecs of M87: jet emission and an elusive accretion disc
We present the first simultaneous spectral energy distribution (SED) of M87
core at a scale of 0.4 arcsec () across the electromagnetic
spectrum. Two separate, quiescent, and active states are sampled that are
characterized by a similar featureless SED of power-law form, and that are thus
remarkably different from that of a canonical active galactic nuclei (AGN) or a
radiatively inefficient accretion source. We show that the emission from a jet
gives an excellent representation of the core of M87 core covering ten orders
of magnitude in frequency for both the active and the quiescent phases. The
inferred total jet power is, however, one to two orders of magnitude lower than
the jet mechanical power reported in the literature. The maximum luminosity of
a thin accretion disc allowed by the data yields an accretion rate of , assuming 10% efficiency. This power
suffices to explain M87 radiative luminosity at the jet-frame, it is however
two to three order of magnitude below that required to account for the jet's
kinetic power. The simplest explanation is variability, which requires the core
power of M87 to have been two to three orders of magnitude higher in the last
200 yr. Alternatively, an extra source of power may derive from black hole
spin. Based on the strict upper limit on the accretion rate, such spin power
extraction requires an efficiency an order of magnitude higher than predicted
from magnetohydrodynamic simulations, currently in the few hundred per cent
range.Comment: 18 pages, 6 figures. Accepted for publication in MNRA
Relationships among main soil properties and three N availability indices.
A biological (aerobic incubation for 3 and 6 weeks) and a chemical method [successive extractions with
cold 0.1 (H1-N) and 0.5 M HCl (H2-N)] were applied to 21 soils to determine: a) the potentially
mineralizable-N; b) the most useful soil variables for predicting soil N availability; and c) their
usefulness for predicting N uptake by a greenhouse wheat crop. At t=3, both net N mineralized (NNM)
and net N mineralization rate (NNMR) were correlated: a) positively with SOM- and CEC-related
variables; and b) positively with soil δ 15N and negatively with soil pH, suggesting that Nmineralization,
dominated by nitrification, is associated with NO3
--N losses and soil acidification. At
t=6, all previously discussed variables were important for NNM, but not for NNMR, mainly controlled
by the available-P content. The importance of H1-N increased with N2-inputs and decreased with NO3
-
losses and soil-N. Relationships of H1-N and H2-N with soil CEC and texture showed the strong
relations among nutrients content, biological activity and N mineralization, as well as the recalcitrance
of clay-bounded SOM. Soil total-N correlations with wheat-N in absolute amount (positive) and as
percentage of soil-N (negative) showed an important supply of available-N by N-rich soils, despite
their slow N turnover. The best regression models for wheat-N always included 1-2 main available
nutrients. The percentage of soil N exported to plant biomass was negatively correlated with noncrystalline
Al compounds and soil δ 15N. Mineralized-N and wheat-N pools did not share many
correlations with soil properties and seemed to come from different sources; consequently, the former
pool, which only explained a quarter of wheat-N variance, was not more useful than soil total-N for
predicting it. Only a positive correlation with soil total-N was shared by wheat-N and hydrolysable-N,
highlighting that the latter N pools are mainly unrelated. Nevertheless, half of wheat-N variation was
explained by its negative relationship with the percentage of soil-N as (H1+H2)-N; a possible
explanation is that chemically labile N is also biologically labile, being cumulated because of a limiting
factor for microbial N mineralization or plant growth and emerging as a good predictor for wheat-N
uptake.Peer reviewe
IBSE: An OWL Interoperability Evaluation Infrastructure
The technology that supports the Semantic Web presents a great diversity and, whereas all the tools use different types of ontologies, not all of them share a common knowledge representation model, which may pose problems when they try to interoperate. The Knowledge Web European Network of Excellence is organizing a benchmarking of interoperability of ontology tools using OWL as interchange language with the goal of assessing and improving tool interoperability. This paper presents the development of IBSE, an evaluation infrastructure that allows executing automatically the benchmarking experiments and provides an easy way of analysing the results. Thus,including new tools into the evaluation infrastructure will be simple and straightforward
Reliability analysis for systems with large hydro resources in a deregulated electric power market
This work describes a procedure that determines the
optimal allocation for the yearly energy resulting from random
water inflows to the different subperiods of a year so that the expected
benefits are maximized. Its main idea is to distribute the
energy stored in reservoirs in each period into two parts: one is
directly sold in the energy market, while the other is made available
to cover any unplanned outages of thermal units. The method
proposed fulfills two objectives, to distribute the hydro energy optimally
according to economic criteria and to assess the impact of
new market rules on the reliability of an electric system. The procedure
will be illustrated by an example based on the Spanish generating
system.This work was supported by the
Project PB-98-0728 of the Ministerio de Educación, Cultura y Deporte, Spain.Publicad
La fisión mediada por DRP1 tiene un papel importante en las enfermedades de Alzheimer y Parkinson
Our objectives were to perform a bibliometric analysis with which to highlight the
role of Drp1 in the pathogenesis of AD and PD as a fundamental regulator of mitochondrial
fusion and fission homeostasis, in addition to highlighting Drp1 as a possible therapeutic target
in AD and PD.Nuestros objetivos son realizar un análisis bibliométrico con el que destacar la relevancia de Drp1 en la patogénesis de la EA y la EP como regulador fundamental de la homeostasis
de la fusión y fisión mitocondrial, además de destacar a Drp1 como posible diana terapéutica en
la EA y la EP.Ciencias Experimentale
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